JSNES and Emulation
If you haven’t seen JSNES or JSSpeccy they’re worth trying out, if only as a way of proving what JavaScript and canvas can do. The most interesting thing about these emulators, though is the source. JSNES is on GitHub so you can casually browse files like cpu.js to see how the emulator works.
In fact, if you’ve never written an emulator but wondered how they work, JSNES is worth checking out. Emulators aren’t really as scary as they sound: they’re essentially decoders that can understand code for particular hardware and run it in a different environment. They’re giant case statements and simple algorithms.
In JSNES, you can see how the CPU registers and interrupts are handled. Since the original hardware has been reverse engineered there’s nothing fundamentally complicated or difficult to understand, there’s just a sizable amount of code.
Now all we need to do is find the source for an x86 emulator to create a JavaScript PC emulator. Browser VMware could be the most computationally extravagant use of JavaScript yet.